Posttraumatic stress disorder (PTSD) is an important and timely clinical issue particularly for combat veterans. Few pharmacologic options are available to treat PTSD, particularly among military personnel, and they are not based on rational neurobiology. The evidence for noradrenergic dysregulation in PTSD is strong, and the alpha-adrenergic agonist prazosin is one of the most promising medications to treat sleep disturbances associated with PTSD as well as PTSD symptoms among both veterans and civilians. Evidence also implicates noradrenergic dysregulation in the pathophysiology of alcohol dependence (AD); prazosin also may have efficacy in treating this disorder. The use of prazosin represents a rational and compelling approach for the treatment of PTSD and comorbid AD. Given the high rates of comorbid AD in trauma survivors with PTSD, and the enormous impact that these comorbid disorders have on psychosocial function and well-being, finding effective treatments for this population is of high clinical importance.